Continuous drive liquid mixing amd metering device

ABSTRACT

A device for mixing two or more substances in which each substance is metered by a separate continuous-flow, positive displacement, volumetric gear pump, then forced together in a mixer manifold, then mixed to homogeneity by forcing through rotating ball, roller, or cone bearings. As an added feature of the invention, the mixer has a purge system permitting one-way flow of either solvent materials or washing materials into the mixer manifold, and a clutch assembly which allows the pumps to be disabled and thus non-delivering while the mixer is being purged. Another feature is valving to permit the introduction of catalysts or the like into the mixer manifold.

United States Patent [191 Jones 1 CONTINUOUS DRIVE LIQUID MIXING AMDMETERING DEVICE [76] Inventor: Richard E. Jones, 780 Broadway,

Redwood City, Calif. 94063 [22] Filed: Jan. 11,1973

2 1] Appl No.: 322,728

[52] US. Cl 259/22; 23/252 R; 222/135;

239/142; 251/357; 259/7 [51] Int. Cl. BOlf 15/02; BOlf 7/14 [58] Fieldof Search 222/135, 145; 259/7, 9,

259/10, 25, 26, DlG. 30, 8, 23, 24, 22; 141/99; 23/252 R; 137/D1G. 3;251/357; 239/142 56] References Cited UNlTED STATES PATENTS 2768.40510/1956 Mineah 2S9/DIG. 30

2,970,773 2/1961 Keryluk et a1. A 2 259/9 UX 3,085783 4/1963 Pulling251/357 X 3,417.923 12/1968 Carlson 239/142 X 1451 July 15, 1975 PrimaryExaminerHarvey C. Hornsby Assistant Examiner-Philip R. C06

(5 7] ABSTRACT A device for mixing two or more substances in which eachsubstance is metered by a separate continuousflow, positivedisplacement, volumetric gear pump.

then forced together in a mixer manifold, then mixed to homogeneity byforcing through rotating ball, roller, or cone bearings. As an addedfeature of the invention, the mixer has a purge system permitting onewayflow of either solvent materials or washing materials into the mixermanifold, and a clutch assembly which allows the pumps to be disabledand thus nondelivering while the mixer is being purged. Another featureis valving to permit the introduction of catalysts or the like into themixer manifold.

14 Claims, 11 Drawing Figures SEE? m ml-HIM ins CONTINUOUS DRIVE LIQUIDMIXING AMD METERING DEVICE SUMMARY OF THE INVENTION This inventionrelates to devices for mixing together materials which upon being unitedform highly viscous or solid substances, and more particularly theinvention relates to a precision meter-mix-dispense system for Urethanefoams, epoxies, resins, elastomers, and polysulfites, that iscontinuous-flow, very accurate, and simple to construct and operate.

Prior art dispensers for metering, mixing, and dispensing Urethane foamand the like have been mainly adaptations of paint spray machines, usingpistons and constrictive values for pumping and metering each component.The length of the piston stroke or oriface determines the amount of eachmaterial injected into the mixer. This arrangement has resulted in veryunreliable metering and maintenance of proper ratio, because the strokesper minute of each piston may vary or pressures may rise and drop.Obviously a piston device does not give a continuous flow of foam, butrather a pulsating stream of material.

There are even greater disadvantages: the piston dispensers are socomplicated in their valving and controls that they require a two mantechnically oriented crew. one to hold the nozzle and another tocontinually adjust the guages, valves, and controls. They are also bulkyand expensive, requiring large pumps, an air pressure source, andusually booms to hold the enormous weight of the mixer and dispensingnozzle.

Prior art mixers were enormously bulky in themselves a typical weightbeing about 40 pounds. The mixers to date have been of the dynamic type,requiring aseparate power source causing paddles, pins, or the like toagitate the two materials to be mixed, the ultrasonic type withassociated electronics, and static mixers, which pass the two substancesthrough a series of stators. So far, mixing effectiveness has been farfrom perfect, so that the foam or other material dispensed has hadsignificant striations of unmixed components.

Another inadequacy in the prior art was the inflexibility of thepump/meter system. Once the pistons were built, the ratios between themwere fixed for all practical purposes. If it were desired to mix anddispense two components in a new ratio, it was necessary to build anentirely new device. Similarly, the delivery rate of the old devices wascompletely non-variable.

In the Urethane and epoxy field, the most dominant factor is the set-uptime of the material once the constituent components are brought intocontact. Since many mixtures harden into solids that are impossible todissolve, wash away, scrape off, or remove in any other manner, mostmeter/mix/dispense systems have had to use disposable mixers or haveincluded a purge system which had the capability of dissolving andwashing out the various substances very quickly. Most such purgesystems, however, have had very short useful lives themselves becausethe Urethane or other material being dispensed would be pressured upinto the purge valves, causing them to jam.

The set-up time" problem can be so acute with some materials that nomechanical dispenser can even be used. For example, where cracks in awall or on some other vertical surface are being epoxied the mix willsag away from the cavity to be filled unless it sets up almostimmediately. In some applications a set-up time as low as one second maybe found.

It is. therefore, the general object of this invention to provide animproved meter/mix/dispenser system for Urethane foam and the like. Onespecific object of the invention is to provide a simple to use, compact,continuous flow dispenser that is accurate and reliable in maintainingthe proper ratio between input components. On an intermittant orcontinuous demand basis and operable by non-technical personnel withminimal instruction.

Another object of this invention is to provide a mixer that leaves nostriations in the output substance and yet is not as bulky and complexas present mixers.

Another object is to provide a meter/pump subsystem that can easily varythe ratio between thhe components being metered and can also vary thedelivery rate of the final mixed product.

In the achievement of the above and other objects and as a feature ofthis invention there is provided a meter/mix/dispense system in whichall components are driven from a common or an easily synchronizablepower source or sources. In the preferred embodiment described below onepower source drives a central shaft from which each pump/meter and themixer as well derive their impetus. As another feature of the inventioneach pump/mixer is a gear pump driven by a common gear pump shaft whichderives its rotary motion from a worm gear on the main drive shaft. Byvarying the chamber and gears of the pump, the volumetric output perrotation can be increased or decreased a very simple operation, as thedetailed description below will show. By alternating the machining wormgear set. i.e., single, double or four threads, mounted on the commonshaft of the pump/meters, the rate of output of the dispenser can bevaried without any danger of varying the ratio between pumps. Thus. themodular features of this invention achieves its object ofeasily-variable metering ratios and output rates.

Another feature of the invention is a mixer which combines theprinciples of dynamic mixers and static mixers by using free wheelingroller bearings-ball bearings, cone bearings, or rodsin the flow path ofthe mixed components. The high shear and milling action imparted to thepressurized fluids as they pass through has been found to achieve almostperfect mixing, in the short space of a half dozen or so bearingsmounted in series and rotated by the central shaft of the dispenser. Ofcourse, it should be pointed out that such a mixer could be actuated bya power source remote from the pump/meter subsystems or through aflexible shaft, without affecting either the ratio of components mixedor the output rate, so that actuation of the mixer by the common driveshaft is merely for purposes of economy, simplicity, and reduction ofbulk and weight.

Another feature of the invention is the capability of introducing purgematerials, blowout air, solvent, as well as a number of liquid andgaseous catalysts or other components with a system of valves that isnot fouled and jammed by the high-pressure Urethane, as was previouslythe problem. This feature consists of mounting between the inlet valvefor each purge liquid or gas a check valve which blocks all back-flow ofUrethane, while opening easily to permit the introduction of fluids inthe opposite direction.

Another feature of this invention is the creation of valve poppets inthe line of flow of the components emerging from the various pump/metersubsystems that could maintain good sealing over long periods of time.The chemical nature of the substances involved together with their highpressure after they emerge from their respective pump/meters makeordinary O-rings useless for sealing purposes. Applicant. however, hasachieved two alternative concepts either of which can maintain sealingindefinitely. One alternative is to assemble a two piece poppet whichsqueezes and traps an O-ring such that enough of the O-ring protrudes toperform sealing, but not enough to be torn away by the pressure. Thesecond alternative is to mold a poppet face of Viton or the like,appropriately shaped to perform sealing. For certain materials a solidmolded poppet of Teflon is required.

Other objects and features of this invention and a better understandingthereof may be had by referring to the accompanying drawings takentogether with the detailed description and claims set forth below.

REFERENCE TO THE DRAWINGS FIG. I is a perspective view of a preferredembodiment of Applicants invention;

FIG. 2 is a side elevation in partial cutaway of the preferredembodiment of Applicant's invention of FIG. 1'.

FIG. 3 is a side elevation in full cutaway of a preferred embodiment ofApplicants invention of FIG. I;

FIG. 4 is a rear elevation in cutaway along the section lines 4-4 ofFIG. 3;

FIG. 5 is a detail view in cutaway along the section lines 55 of FIG. 3;

FIG. 6 is a detail view in cutaway along the section lines 6-6 of FIG.3;

FIG. 7 is a top view in partial cutaway of the preferred embodiment ofApplicants invention of FIG. I;

FIG. 8 is a top view in full cutaway of the preferred embodiment ofApplicants invention of FIG. 1;

FIG. 9 is a detail view in partial section of a meter output valveaccording to Applicant's invention;

FIG. 10 is a detail section view of an improved poppet according toApplicants invention; and

FIG. II is a side elevation in partial cutaway of the mixer assembly(including mixer, three way purge valve, purge check valve. and thirdcomponent inlet provision and nozzle) of the preferred embodiment ofApplicants invention.

DETAILED DESCRIPTION Referring to FIG. I, the preferred embodiment ofApplicants invention shown therein comprises a power source to. whichmay be any prior art electrical, air, or other drive means. In theactual device built according to this detailed description, a RockwellManufacturing Company Model 757 electrical drive was used. This powersource has a handle 4, an electrical cord 6, a grip 8, a trigger switch10, a trigger lock 12, and a reverse switch 14. The controls l0, l2, and14 operate an electrical motor 16 which is mounted upon the main body ofthe dispenser system.

The central works of the dispenser system, to be described in connectionwith later drawings, are covered by a body cowling 20 having a greasefitting 21 through which lubrication and a grease barrier between sealsmay be introduced. Underneath the body cowling 20 is 4 a yoke assembly22 upon which the gear pumps 23 are mounted. Each gear pump 23 in thepreferred embodiment that was constructed was an Eastern Industries 2100Series Fluid Motor.

By convention in the Urethane dispensing fluid, the right hand side of adispenser is said to be the recipient of the A" component of theUrethane foam. The left hand side handles the B" component. Accordingly,at 24 B of FIG. 1 a component input hose leads to an input fitting 26Bof the left hand gear pump 23. B component would be supplied through theinput hose 248 by gravity, pump pressure or air pressure appliedupstream at the storage container, all as is well known in the priorart.

The meter/mix/dispense system of FIG. I is carried and supported by ahandle 30 and legs 32 and 34, which are affixed to the yoke assembly 22by screws 36 which pass through the gear pumps 23. Forward of the yokeassembly 22 is a mixer assembly 40, including a mixer manifold housing42 wherein the A component and the B component come together for thefirst time, the mixer 44 and an outlet nozzle 46. Mounted upon the mixermanifold housing 42 is a purge system 50 including an inlet 52 forsolvents, an inlet 54 for blowing agents and or air, and a handle 56 fora three-way valve which can alternatively admit fluids from the inlet52, admit fluids from the inlet 54, or permit no flow at all into themixer manifold 42.

Referring still to FIG. 1 it can be seen there that each gear pump 23 ismade up of three sections 60, 62, and 64; the inner section 60 nearestthe yoke assembly 22 being referred to herein as the input or driveside, the middle section 62 being referred to herein as the centerplate, and the outermost section 64 being referred to as the rear side.The three sections 60, 62, and 64 are assembled to the yoke assembly 22by first stacking, then inserting pump assembly screws 66, and finallymounting the stack to the yoke assembly 22 with pump mounting screw 68.

Referring to FIG. 2, the partial cutaway of the A side gear pump 23shown therein shows the inner works of the gear pump 23 as they wouldappear if the rear side plate 64 were not present. The center plate 62is shown to have an inner cavity in which are fitted a drive gearrotatable by a drive shaft 101 and a secondary gear 102 which rotatesfreely on a secondary shaft 103. The teeth of the drive gear 100 meshwith the teeth of the secondary gear 102 to transfer rotary motion fromthe drive shaft l0l thereto. A fluid to be pumped by the rotation of thegears I00 and 102 enters through an input port 104 at the end of inputfitting I06 fed by an input hose I08 in the manner explained inconnection with the hose 24 and fitting 26 of the B side in FIG. I. TheA component forced into the gear pump shown in FIG. 2 exits through anoutput port I10 into a valve in the yoke assembly 22 that will bedescribed in connection with FIGS. 7, 9, and 10.

At this point in the Detailed Description several of the importantfeatures of Applicant's invention can be appreciated. The feature ofaccurate metering and continuous flow dispensing is achieved by drivingseparate components through the separate gear pumps 23 to be unitedunder pressure in the mixer manifold 42. The very important feature ofproviding variability of the ratio of A component to B component isachieved simply by varying the thickness of the center plate 62 andmatching gear sets 100 and 102 of one or both gear pumps 23. Variationof the thickness of either center plate 62 and gear sets 100 and 102carries with it a concomitant variation of the volume of the cavitywithin the center plate and of the gears 100 and 102. By selecting gearswith larger or smaller tooth configurations, metering output and ratioscan also be adjusted. This is a very important advantage when ratios ofover to 1 are required. Thus by supplying matched sets of center plates62, gears 100 and 102, as well as screws 36, 66, and 68 and shafts 101and 103, it is possible to give one dispenser according to thisinvention the capability of metering components in a variety of ratios.

in connection with FIG. 2 it can be seen that a dis penser according tothe invention is small enough and simple enough to be carried andoperated by a single person. Likewise the use of flexible, lengthy inputhoses 108 and supply tubes as shown at 52 for the inputs to the purgesystem 50 permits the dispenser to be moved wherever desired,constituting a great improvement over the bulky, boom-suspension,two-man rigs available at the present time.

Referring to FIG. 3, the drive train of the dispenser begins at anarmature output shaft 201 of the electric motor 16, or, of course, atthe output shaft of any comparable power supply. The yoke assembly 22has a power supply interface plate 200 through which the output shaft201 protrudes, with a gear 202 mounted thereon. Four mounting screws 204secure the yoke through the interface plate 200 to the power source. Amain drive shaft 206 is mounted within the yoke assembly 22 with itsrear bearing 208 mounted on the power supply interface plate 200. Areduction gear 210 mounted on the drive shaft 206 meshes with the outputgear 202 to transmit power therefrom. The forward end of the drive shaft206 culminates in a drive shaft cartridge 220 which includes a frontbearing 222, and front and rear seals 224 and 226.

Riding on the main drive shaft 206 just forward of the reduction gear210 is a clutch housing and tang 230 with clutch 232 engaging a worm240, which rotates freely about the drive shaft 206. The worm 240 iscoupled to the clutch housing and tang 230 by a worm tang 242, theoverall effect being that power from the drive shaft 206 is transmittedto the worm 240 when the electrical motor 16 is in forward, whileleaving the worm 240 free to rotate whenever the reverse switch 14 isactivated to purge the mixer 44. The worm 240 has a certain length ofworm threads 244 and a thrust bearing and washer assembly 246 whichoccupy between them the full length of the shaft 206 between the clutchhousing 230 and the drive shaft cartridge 220. As another feature ofthis invention, the replacement of a worm 240 with another having adifferent number of threads 244, i.e., varying the worm pitch will varythe output rate of the dispenser, assuming that the power source 2 is ofconstant speed, in a manner to be described hereinafter.

Power from the worm 240 is transmitted to the gear pumps 23 through adrive train having as its next component a worm gear 250 with worm gearteeth 252, in the preferred embodiment actually constructed, 30 innumber. A worm gear hub 254 is secured via a worm gear roll pin 256 to acentral pump shaft 260 which, as will be described hereinafter, isdirectly connected to the drive shafts 101 of the gear pumps 23. Thusrotation imparted to the worm 240 via the clutch 232 is directly coupledto rotate the pump gears 100 and 102.

The drive shaft 206 not only powers the worm 240 but also is tanged at346 to the stacked roller bearings 350 within the mixer 44, so that saidroller bearings 350 rotate whenever the electric motor 16 is operatedeither in forward or in reverse. When the electric motor is operated inforward the gear pumps 23 also operate, forcing A and B components intothe mixer manifold 42, through the bearings 350 into the output cavity360 and thence out the nozzle 46. When the electric motor 16 is inreverse, no A and B component is pumped by the gear pumps 23, but thedrive shaft 206 still rotates the bearings 350. in this mode, solventfrom 52 and air grom 54 may be valved into the mixer manifold 42 topurge the mixer.

As stated in the Summary section of this specification, one feature ofthis invention is the ability to perform instant purging at any timewith a valve system that is not fouled by the highpressure A and Bcomponent. This object has been achieved with great reliability andlongevity by the employment of a purge check valve 370 between thethree-way valve 52S456 and the mixer manifold 42.

Referring to FIG. 4 the rear view of the cut away yoke assembly 22 showsthe paths of the input ports 104A and 1048 and the output ports 110A and1108. The ports originate in the outer face of each drive side 60. Theseouter faces, of course, form one boundary of the pressure chamber inwhich the gears and 102 do their pumping. The ports 104 pass through thedrive side to the input fittings 26 and 106. The ports pass through thedrive sides 60 to enter the yoke assembly 22 where they culminate in twovalve chambers 311 to be described in greater detail below. lnasmuch asthe ports 110 must be drilled in solid material of the yoke assembly 22,plugs 109 are used to close off the ends where the drill entered thematerial. To avoid leakage at the boundary between the drive sides 60and the yoke assembly 22, O-rings 111A and 111B are employed. FIGS. 5and 6 show the relationship between the output ports 110, the valvechambers 311, and the ball bearings 350 through which the A and Bcomponents flow on their way to being dispensed.

Referring to FIG. 7 the purpose of the A and B valves in the yokeassembly 22 is both to prevent the seepage of A and B component due tosupply pressures when the gear pumps 23 are not creating pressure and toprevent purge material from backing into the gear pumps. Accordingly,high pressure A and B component from the output port 110 must passthrough valve cavities 311A and B before reaching the inside 342 of themixer manifold through orifices at the valve seats 302. The valvesconsist of a valve stem 310A and 3108, terminating in a poppet 312A and312B which must interact with its respective valve seat 302 to form aperfect seal against high pressure flow from 110. The concepts wherebythis sealing capability is achieved constitute additional features ofthis invention which will be discussed in detail in connection withFIGS. 9 and 10.

At its other end each stem 310 passes through a bear ing 320 in thestructure of the yoke 22. The bearing 320 is shaped to contain an O-ring322 which seals the gear bearing and is held in place by a from springlocater 324. Beyond each bearing 320 A or B is a spring 326 A or Brunning between its respective front spring locater 324 and a rearspring locater 328 which is positioned by a tightening nut 329 screwedupon threads 330 at the rear end of the stem 310.

The strength of the spring 326 is chosen to ensure that the poppets 312A and B will be held closed when the gear pumps 23 are not creatingpressure, while, of course, permitting the poppets 312 to open when A orB component is being pumped from 23. The nut 329 adjustment threads 330combination permits the tension of the springs 326 to be increased ordecreased very quickly and simply, depending upon the supply pressureassociated with different A and B components. As a notable example, whenthe Polyol is employed on the B side in the dispensing of Urethane foam,a high supply pressure is necessary because of the high viscosity ofPolyol. The supply pressure, as was explained in connection with FIGS. 1and 2, originates in or near the container from which the component isforced through the input hoses 24 or 108. Thus in the operation of adispenser, the supply pressure would not be cut off every time the motor16 is put in reverse for the purge operation. When an unusually highsupply of pressure is encountered, as with Polyol, the purge operationwould be spoiled by partial opening of a poppet 312, were it not for thecapability at 329 330 for increasing closing force. i.e., tension of thespring 326 exerted against the rear spring locater 328 and nut 329 toexert a closing force on the stem 310).

The plan view of FIG. 7 is also an appropriate place to describe indetail the mixer which is an important feature of this invention. A or Bcomponent emerging at 302 enters the mixer manifold interior 342 undervery high pressure. The only path of escape is through a series of ballbearings 350, each having an inner race 352 affixed to the mixer driveshaft 344. Each outer race 354 is mounted directly to the mixer housing44. Between the inner races 352 and outer races 354 are the balls 356.The high pressure A and B component traverses each ball bearing 350 viathe annulus 358. Since the mixer drive shaft 344 is tanged to the maindrive shaft 206 at 346, as described in connection with FIG. 3, wheneverthe main drive shaft is rotating in the forward direction to cause thegear pumps 23 to create pressure, the mixer drive shaft 344 will rotate,and with it, the ball bearing inner races 352. As the component isforced through each annulus 358, the shear between the inner race 352and the immobile outer race 354 together with the shear of the rotatingballs 356 creates an extreme mixing and milling effect that results in aunified substance completely free of striation emerging from the nozzle46.

Referring to FIG. 11, the mixer shown there is an alternative embodimentof the mixer-bearing concept using cone bearings having an outer race950 and an inner race 952, cones 954, and annulus 956 through which theA and B component is forced. Although the ball bearings shown in FIG. 7are more common, less expensive, and thus easier to procure forreplacement purposes, the cone bearings actually supply a greater shearand turbulence, if this is desired for some special application. Rollerbearings are an obvious extension of this concept.

Referring to FIG. 8, the plan view shown there is cut away to reveal theinner works of the gear pumps 23. The worm gear 240 and its shaft 260(the central pump shaft described in connection with FIG. 3) can be seento be mounted within the yoke 22 with a thrust bearing 800 and thrustwashers 802 to ensure proper centering of the gear 240 and take upthrust load. The central pump shaft 260 is mounted rotatably upon theyoke 222 by the use of two needle bearings 812, and transmits rotarymotion to the pump drive shafts 101 A and B via tangs 810.

Each gear pump 23 is capable of exerting extremely high pressureemanating from the cavities within the center plates 62. Accordingly, itis necessary that the mechanical coupling between the worm gear 240 andthe drive gear be well sealed somewhere along the axes of the shafts 101and 260. This is accomplished by the mounting of high pressure seals at820 together with washers 814 and 822 and retainer ring 824.

Further details observable in FIG. 8 include needle bearings 826 uponwhich the shafts 101 and 103 are mounted rotatably into the plates 60and 64 and dowels 828 which keep the plates 60-62-64 in perfectalignment, Gear pins 830 passing through the gears 100 and 102 and theirshafts 101 and 103 cause the gears to be affixed to the shafts. PumpO-rings 831 ensure sealing of plates 60-62-64.

Referring to FIG. 9 the detailed view of the valve system describedabove in connection with FIG. 7 illustrates one new poppet-sealingconcept that is a feature of this invention. The solid poppet 312 of theprior art is divided into an inner poppet 900 and an outer poppet 902which are completely separate parts in order to permit the manufactureupon one or the other (here, the outer poppet 902) of an O-ring dovetail906 a cavity shaped to trap an O-ring 910 sufficiently that it will notbe ripped away by the high pressures created by the gear pumps 23. Inthe preferred embodiment shown in FIG. 9, the inner poppet 900 isintegral with the shaft 310 and the outer poppet 902 is mounted upon theshaft 310, after the fitting of the outer O-ring 910 and an inner O-ring912, by the emplacement of a poppet tightening screw 920 and lock washer922 screwing into an internal tap 924 in the shaft 310.

Referring to FIG. 10, the poppet 312 shown therein is onepiece, andaccording to the invention has a molded face 930 of appropriatematerial, in the actual embodiment constructedViton. The molded face isappropriately shaped as at 931 to perform sealing against the face 302.In the preferred practice of this particular poppet concept the poppetis screwed onto the shaft 310 by threads 932 that have been coated withepoxy just before threading. Alternatively, a bolt and lock washer couldbe used to hold the poppet 312 of FIG. 10 in place. For certain chemicalmaterials being processed it would be advantageous to machine thecomplete poppet configuration 312 from a material such as Teflon, Nylon,or polypropolene, due to their non-reactive properties.

Referring to FIG. 6 again, another feature of Applicant's dispenserconcept is an inlet fitting 500 mounted upon the mixer manifold 42, topermit the introduction of a variety of fluids that might be necessaryor advantageous into the mixture passing through the bearings 350. Insome applications, catalysts and accelerators would be passed in at 500.In other cases, blowing agents would be introduced under pressure, Freonbeing the most-used. Such a blowing agent decreases the density of thedispensed mix and facilitates penetra tion of confined areas(cg-telephone coaxial cable). To prevent escape of high pressure A" and3" component, a check valve 501 protects the supply source upstream ofthe fitting 500.

In the operation of the meter/mix/dispenser described above a singleperson can perform all tthe operations with one hand holding the grip 8and another holding the handle 30 for exact positioning of the nozzle46. Since the features describedabove permit the construction of adispenser weighing approximately 13 pounds. there is nothing slow,clumsy, or inaccurate associated with manipulating the dispenser withoutthe aid of suspension booms or the like. The dispenser is flexiblyconnected to all its supply sources via the electrical cord 6, thecomponent hoses 24 and 108, and such fluid tubing as is shown at 52.

Thus prepared, the operator dispenses Urethane foam or the like bysimply activating the trigger switch to cause the electric motor 16 torotate in the forward direction. As explained before, when the motor 16operates in forward the main drive shaft 206 not only rotates the ballbearings 350 but also rotates the clutch 232 and and B the worm 240 tocause the gear pumps 23 to operate. Operation of the gear pumps 23causes A anelB component arriving at the fittings 26 and 106 to bepumped at high pressure out the output ports 110 into the manifold 42,where they enter the mixer 44 and emerge as one substance to bedispensed out the nozzle 46.

The purge operation, which is necessary whenever there is a momentshesitation in dispensing, was in prior art devices performed by removingthe mixer and washing it in solvent. The vast time saving permitted byApplicant's dispenser is shown by the simplicity of purging the mixer:the operator need only activate the reverse switch 14, and then pressthe trigger 10 while switching the three-way handle 56 to introducesolvent 52 and then air 54 into the manifold 42, from which it passesthrough the ball bearings 350 and out the nozzle 46. This accomplishesthorough cleaning and the equipment is in readiness for its next use.

The following applications have been performed by dispensers builtaccording to the principles of this invention without fouling the valvesor the mixer, even with the very short set-up times (pot-life") shown insome instances:

of H147 between the gears 202 and 210. The worm 240/worm gear 250 setsutilized drove the gear pumps 23 at either 160 rpm, 320 rpm, or 640 rpm,depending on the dispense rate desired.

When an air drive unit is used at 16 the output shaft 20] rotates atabout 10,000 rpm, reduced to 7,500 rpm by the gear 202, 210. An airpower supply has the advantage of greater horse power, about 3 H.P., ascompared -to 1 HP. for the Model 757. Moreover, air power is an absolutenecessity wherever explosionproof equipment is required by the workrules.

Although the various features of this invention have been described witha certain degree of particularity for purposes of illustration, itshould be emphasized that the production to which Applicant is entitledextends to the full range of the inventive concept described in theclaims below.

The inventive concepts for which protection is claimed are described asfollows:

I. A multi-liquid metering and mixing dispenser for volumetricallymetering a plurality of separate liquid components introduced into saiddispenser through the plurality of separate input ports, then mixingtogether the metered volumes of said components, then dispensing theresulting mixture of said components, including:

a. a power source disposed for delivering power in a forward mode and areverse mode;

b. a first metering means disposed for being driven by said power sourceand operatively associated with a first one of said separate input portsto receive a first said liquid component;

c. a second metering means disposed for being driven by said powersource and operatively associated with a second one of said separateinput ports to receive a second said liquid component;

d. said first metering means and said second metering means beingoperatively associated with said power source and with one another insuch manner that the volumetric ratio of said first liquid componentThus it can be seen that Applicant has invented a highly flexible,easily-operated meter/mix/dispenser system which can utilize a singlepower source for all functions. In the alternative, the inventiveconcepts could be performed with separate power for the mixer 44,especially if it is desired to have the mixer 44 and nozzle 46 remotefrom the gear pumps 23, where space is confined. Similarly, two or moregear pumps 23 could meter equally well if they were operated by separatepower sources but were synchronized or servoe to maintain accurateratio.

The inventive dispenser can be employed with either an electrical powersource as shown at 16 or an air drive power source. Using the RockwellManufacturing Company Model 757 electrical drive. the output of thearmature 201, 20,000 rpm, was reduced by a gear ratio to said secondliquid component remains fixed whenever said power source is drivingsaid metering means;

e. mixing means operatively associated with said first metering meansand said second metering means to receive said first liquid componentand said second liquid component, said mixing means having thecapability of intermixing said first liquid component and said secondliquid component to form a substantially homogenous mix; and

. means connected between said power source and said first and secondmetering means and said mixing means for driving said first and secondmetering means only in the forward mode of said power source and fordriving said rfiixing means in both the forward mode and the reversemode of said power source.

2. The multi-liquid metering and mixing dispenser of claim 1 furtherincluding a manifold mounted between said first metering means and saidsecond metering means and said mixing means. said manifold being adaptedto receive said first liquid component and said second liquid componentseparately from said first metering means and said second meteringmeans. respectively. and to pass said first liquid component and saidsecond liquid component together into said mixing means.

3. The multi-liquid metering and mixing dispenser of claim 2, furthercomprising first protective means mounted between said first meteringmeans and said manifold and adapted to prevent all fluid flow in eitherdirection between said first metering means and said manifold wheneversaid first metering means is not operating, and second protective meansmounted between said second metering means and said manifold and adaptedto prevent all fluid flow in either direction between said secondmetering means and said manifold whenever said second metering means isnot operating.

4. The multi-liquid metering and mixing dispenser of claim 1 with thefollowing additional limitations:

a. a manifold mounted between said first metering means and secondmetering means and said mixing means. said manifold being adapted toreceive said first liquid component and said second liquid componentseparately from said first metering means and said second meteringmeans, respectively, and to pass said first liquid component and saidsecond liquid component together into said mixing means; and

b. valve means mounted upon said manifold for introducing fluids intosaid manifold from sources other than said first liquid component andsaid second liquid component.

5. The multi-liquid metering and mixing dispenser of claim 4 with thefollowing additional limitation:

a. a first protective means mounted between said manifold and said valvemeans and adapted to prevent all fluid back-flow from said manifold tosaid valve means while permitting free flow from said valve means tosaid manifold.

6. The multi-liquid metering and mixing dispenser of claim 4 with thefollowing additional limitations:

a. a second protective means mounted between said first metering meansand said manifold, and adapted to prevent all fluid flow in eitherdirection between said first metering means and said manifold wheneversaid first metering means is not operating; and

b. a third protective means mounted between said second metering meansand said manifold, and adapted to prevent all fluid flow in eitherdirection between said second metering means and said manifold wheneversaid second metering means is not operating.

7. A multi-liquid metering and mixing dispenser for volumetricallymetering a plurality of separate liquid components introduced into saiddispenser through a plurality of separate input ports. then mixingtogether the metered volumes of said components, then dispensing theresulting mixture of said components, including:

a. a power source disposed for delivering power in a forward mode and areverse mode;

b. a first gear pump disposed for being driven by said power source andcoupled to a first one of said separate input ports to receive a firstsaid liquid component;

c. a second gear pump disposed for being driven by said power source andcoupled with a second one of said separate input ports to receive asecond said liquid component; said first gear pump and said second gearpump being mechanically connected to said power source in such mannerthat the volumetric ratio of said first liquid component to said secondliquid component remains fixed whenever said power source is drivingsaid gear pumps;

d. a mixer coupled to output ports of said first gear pump and saidsecond gear pump to receive said first liquid component and said secondliquid component, said mixer having the capability of intermixing saidfirst liquid component and said second liquid component to form asubstantially homogenious mix; and

e. means connected between said power source and said first gear pump,said second gear pump, and said mixer for driving said first gear pumpand said second gear pump only in the forward mode of said power sourceand for driving said mixer in both the forward mode and the reverse modeof said power source.

8. The multi-liquid metering and mixing dispenser of claim 7 furtherincluding a manifold mounted between said first and second gear pumpsand said mixer. said manifold being adapted to receive said first liquidcomponent and said second liquid component separately from said firstgear pump outlet port and said second gear pump outlet port.respectively. and to pass said first liquid component and said secondliquid component together into said mixer.

9. The multi-liquid metering and mixing dispenser of claim 8 furtherincluding a first protective valve mounted between said first gear pumpand said manifold and adapted to prevent all fluid flow in eitherdirection between said first gear pump and said manifold whenever saidfirst gear pump is not operating, and a second protective valve mountedbetween said first gear pump and said manifold and adapted to preventall fluid flow in either direction between said second gear pump an saidmanifold whenever said second gear pump is not operating.

10. The multi-liquid metering and mixing dispenser of claim 7 with thefollowing additional limitations:

a. a manifold mounted between said first and second gear pumps and saidmixer, said manifold being adapted to receive said first liquidcomponent and said second liquid component separately from said firstgear pump outlet port and said second gear pump outlet port,respectively, and to pass said first liquid component and said secondliquid compo' nent together into said mixer; and

b. a fluid introduction valve system mounted upon said manifold forintroducing fluids into said manifold.

11. The multi-liquid metering and mixing dispenser of claim 10 with thefollowing additional limitation:

a. a one-way flow valve mounted between said manifold and said fluidintroduction valve system to prevent all back-flow from said manifold tosaid valve system while permitting free flow from said valve system tosaid manifold 12. The multi-liquid metering and mixing dispenser ofclaim with the following additional limitations:

a. a first protective valve mounted between said first gear pump andsaid manifold, and adapted to prevent all fluid flow in either directionbetween said first gear pump and said manifold whenever said first gearpump is not operating; and b. a second protective valve mounted betweensaid second gear pump and said manifold, and adapted to prevent allfluid flow in either direction between said second gear pump and saidmanifold whenever said second gear pump is not operating. 13. Themulti-liquid metering and mixing dispenser of claim 1 wherein the powersource is directly coupled to said mixer and wherein said driving meansincludes a clutch and wherein said power source is coupled to Said firstgear pump and to said gear pump through said clutch which transmitspower in one direction of rotation and does not transmit power in theopposite direction of rotation.

14. The multi-liquid metering and mixing dispenser of claim 1 whereinsaid power source is directly coupled to said mixing means and whereinsaid driving means includes a clutch and said power source is coupled tosaid first metering means and to said second metering means through saidclutch which transmits power in one direction of rotation and does nottransmit power in the opposite direction of rotation.

1. A multi-liquid metering and mixing dispenser for volumetricallymetering a plurality of separate liquid components introduced into saiddispenser through the plurality of separate input ports, then mixingtogether the metered volumes of said components, then dispensing theresulting mixture of said components, including: a. a power sourcedisposed for delivering power in a forward mode and a reverse mode; b. afirst metering means disposed for being driven by said power source andoperatively associated with a first one of said separate input ports toreceive a first said liquid component; c. a second metering meansdisposed for being driven by said power source and operativelyassociated with a second one of said separate input ports to receive asecond said liquid component; d. said first metering means and saidsecond metering means being operatively associated with said powersource and with one another in such manner that the volumetric ratio ofsaid first liquid component to said second liquid component remainsfixed whenever said power source is driving said metering means; e.mixing means operatively associated with said first metering means andsaid second metering means to receive said first liquid component andsaid second liquid component, said mixing means having the capability ofintermixing said first liquid component and said second liquid componentto form a substantially homogenous mix; and f. means connected betweensaid power source and said first and second metering means and saidmixing means for driving said first and second metering means only inthe forward mode of said power source and for driving said mixing meansin both the forward mode and the reverse mode of said power source. 2.The multi-liquid metering and mixing dispenser of claim 1 furtherincluding a manifold mounted between said first metering means and saidsecond metering means and said mixing means, said manifold being adaptedto receive said first liquid component and said second liquid componentseparately from said first metering means and said second meteringmeans, respectively, and to pass said first liquid component and saidsecond liquid component together into said mixing means.
 3. Themulti-liquid metering and mixing dispenser of claim 2, furthErcomprising first protective means mounted between said first meteringmeans and said manifold and adapted to prevent all fluid flow in eitherdirection between said first metering means and said manifold wheneversaid first metering means is not operating, and second protective meansmounted between said second metering means and said manifold and adaptedto prevent all fluid flow in either direction between said secondmetering means and said manifold whenever said second metering means isnot operating.
 4. The multi-liquid metering and mixing dispenser ofclaim 1 with the following additional limitations: a. a manifold mountedbetween said first metering means and second metering means and saidmixing means, said manifold being adapted to receive said first liquidcomponent and said second liquid component separately from said firstmetering means and said second metering means, respectively, and to passsaid first liquid component and said second liquid component togetherinto said mixing means; and b. valve means mounted upon said manifoldfor introducing fluids into said manifold from sources other than saidfirst liquid component and said second liquid component.
 5. Themulti-liquid metering and mixing dispenser of claim 4 with the followingadditional limitation: a. a first protective means mounted between saidmanifold and said valve means and adapted to prevent all fluid back-flowfrom said manifold to said valve means while permitting free flow fromsaid valve means to said manifold.
 6. The multi-liquid metering andmixing dispenser of claim 4 with the following additional limitations:a. a second protective means mounted between said first metering meansand said manifold, and adapted to prevent all fluid flow in eitherdirection between said first metering means and said manifold wheneversaid first metering means is not operating; and b. a third protectivemeans mounted between said second metering means and said manifold, andadapted to prevent all fluid flow in either direction between saidsecond metering means and said manifold whenever said second meteringmeans is not operating.
 7. A multi-liquid metering and mixing dispenserfor volumetrically metering a plurality of separate liquid componentsintroduced into said dispenser through a plurality of separate inputports, then mixing together the metered volumes of said components, thendispensing the resulting mixture of said components, including: a. apower source disposed for delivering power in a forward mode and areverse mode; b. a first gear pump disposed for being driven by saidpower source and coupled to a first one of said separate input ports toreceive a first said liquid component; c. a second gear pump disposedfor being driven by said power source and coupled with a second one ofsaid separate input ports to receive a second said liquid component;said first gear pump and said second gear pump being mechanicallyconnected to said power source in such manner that the volumetric ratioof said first liquid component to said second liquid component remainsfixed whenever said power source is driving said gear pumps; d. a mixercoupled to output ports of said first gear pump and said second gearpump to receive said first liquid component and said second liquidcomponent, said mixer having the capability of intermixing said firstliquid component and said second liquid component to form asubstantially homogenious mix; and e. means connected between said powersource and said first gear pump, said second gear pump, and said mixerfor driving said first gear pump and said second gear pump only in theforward mode of said power source and for driving said mixer in both theforward mode and the reverse mode of said power source.
 8. Themulti-liquid metering and mixing dispenser of claim 7 further includinga manifold mounted between said first and second gear pumps and saidmixer, said manifold being adapted to recEive said first liquidcomponent and said second liquid component separately from said firstgear pump outlet port and said second gear pump outlet port,respectively, and to pass said first liquid component and said secondliquid component together into said mixer.
 9. The multi-liquid meteringand mixing dispenser of claim 8 further including a first protectivevalve mounted between said first gear pump and said manifold and adaptedto prevent all fluid flow in either direction between said first gearpump and said manifold whenever said first gear pump is not operating,and a second protective valve mounted between said first gear pump andsaid manifold and adapted to prevent all fluid flow in either directionbetween said second gear pump an said manifold whenever said second gearpump is not operating.
 10. The multi-liquid metering and mixingdispenser of claim 7 with the following additional limitations: a. amanifold mounted between said first and second gear pumps and saidmixer, said manifold being adapted to receive said first liquidcomponent and said second liquid component separately from said firstgear pump outlet port and said second gear pump outlet port,respectively, and to pass said first liquid component and said secondliquid component together into said mixer; and b. a fluid introductionvalve system mounted upon said manifold for introducing fluids into saidmanifold.
 11. The multi-liquid metering and mixing dispenser of claim 10with the following additional limitation: a. a one-way flow valvemounted between said manifold and said fluid introduction valve systemto prevent all back-flow from said manifold to said valve system whilepermitting free flow from said valve system to said manifold.
 12. Themulti-liquid metering and mixing dispenser of claim 10 with thefollowing additional limitations: a. a first protective valve mountedbetween said first gear pump and said manifold, and adapted to preventall fluid flow in either direction between said first gear pump and saidmanifold whenever said first gear pump is not operating; and b. a secondprotective valve mounted between said second gear pump and saidmanifold, and adapted to prevent all fluid flow in either directionbetween said second gear pump and said manifold whenever said secondgear pump is not operating.
 13. The multi-liquid metering and mixingdispenser of claim 1 wherein the power source is directly coupled tosaid mixer and wherein said driving means includes a clutch and whereinsaid power source is coupled to said first gear pump and to said gearpump through said clutch which transmits power in one direction ofrotation and does not transmit power in the opposite direction ofrotation.
 14. The multi-liquid metering and mixing dispenser of claim 1wherein said power source is directly coupled to said mixing means andwherein said driving means includes a clutch and said power source iscoupled to said first metering means and to said second metering meansthrough said clutch which transmits power in one direction of rotationand does not transmit power in the opposite direction of rotation.